1. Field of the Invention
The invention relates to cutting machines such as mowing or harvesting machines. More particularly, the invention relates to cutting machines which are connected or hitched to a power driven vehicle.
2. Discussion of the Background
The invention relates to cutting machines which include a hitching structure intended to be connected to the hitch of a power-driven vehicle. In particular, a cutting mechanism is provided which extends, during work, crosswise to the direction of work (i.e., crosswise with respect to the moving direction of the vehicle) with a first connection device connecting the cutting mechanism to the hitching structure. The first connection device is connected to the cutting mechanism at least approximately in the vicinity of a first longitudinal end of the cutting mechanism and allows the cutting mechanism to pivot in relation to the hitching structure around a geometric axis which is directed forwardly. A first load-lightening element is used to lighten the first longitudinal end of the cutting mechanism, with a wheel placed in the vicinity of a second longitudinal end of the cutting mechanism and which rolls over the ground during work. A second connection device connects the wheel to the cutting mechanism, with the second connection device being connected to the cutting mechanism at least approximately in the vicinity of the second longitudinal end of the cutting mechanism to allow displacement of the height of the cutting mechanism in relation to the wheel. In addition, a second load-lightening element is provided to lighten the second longitudinal end of the cutting mechanism.
In patent application EP 0 361 573, a known mower is described. The hitching structure of this known mower is fastened to the three-point hitch of the tractor and the mowing group extends next to the path of the tractor perpendicular to the direction of work. The first longitudinal end of the mowing group is connected to the hitching structure by a pivot pin with a geometric axis directed or extending parallel to the direction of work. With this structure, the mowing group is able to pivot in relation to the hitching structure around the geometric axis of the pivot pin, to adapt to the contour of the ground. A first spring, installed between the hitching structure and the mowing group, also lightens the mowing group while tending to cause it to pivot around the pivot pin.
The mowing group, moreover, rests on two wheels, each installed behind a longitudinal end of the mowing group. The rolling axis of each wheel is more precisely connected to the mowing group by a vertically deformable parallelogram on which a spring acts. The latter tends to deform the parallelogram so as to lighten the corresponding longitudinal end of the mowing group.
This known mower exhibits several drawbacks.
Considering that the mowing group of this known mower is connected to the hitching structure by a pivot pin, the hitching structure is connected rigidly to the hitch of the tractor and the mowing group can adapt to the contour of the ground only by pivoting around the geometric axis of said pivot pin. Since the displacement in height of the mowing group is considerably limited because of this, the adaptation of the mowing group to the contour of the ground is therefore very imperfect.
Considering such an arrangement, the first longitudinal end of the mowing group is, in addition, poorly lightened.
An additional drawback of this known mower further appears at the level of the wheels which are directed in the direction of work and located far back from the rear wheels of the tractor. As a result, the wheels skid on the ground when the driver of the tractor is led to take tight turns.